A qualitative mathematical model is presented that examines membrane potential feedback on synthesis of inositol 1,4,5-trisphosphate (IP₃), and its role in generation and modulation of slow waves. Previous experimental studies indicate that slow waves show voltage dependence, and this is likely to result through membrane potential modulation of IP₃. It is proposed that the observed response of the tissue to current pulse, pulse train, and maintained current injection can be explained by changes in IP₃, modulated through a voltage-IP₃ feedback loop. Differences underlying the tissue responses to current injections of opposite polarities are shown to be due to the sequence of events following such currents. Results from this model are consistent with experimental findings and provide further understanding of these experimental observations. Specifically, we find that membrane potential can induce, abolish, and modulate slow wave frequency by altering the excitability of the tissue through the voltage-IP₃ feedback loop.